The Periwinkles and - Chink Shells - Family Littorinidae

Habitat.—Florida to New York.

The Rough Winkle (L. rudis, Don) is at best scarcely half an inch in length, with rounded whorls separated by deep sutures. The female carries her eggs until they hatch, hence the last whorl is fully two-thirds of the whole shell and the round mouth is much larger than that of a male shell of equal size. This species is banded in neutral colours, from yellow to black. It can live out of water for a week. Marked specimens on the rocks were found not to have moved for over a month. The shells of the young brood render these periwinkles inedible. Their size, also, makes them hardly worth while. Length, to inch.

Habitat.— Atlantic and Pacific coasts.

The Gray Littorina (L. planaxis, Nutt.) is known by the broad, flat excavation of the columella. The shells are smooth rather thick, dirty white, flamed in irregular, often handsome patterns. The young shells lose their brightness with age. The average diameter is inch.

Habitat.— California.

The Checkered Littorina (L. scutellata, Gld.) is brown or olive, checkered with white. The average shells are inch or less in length. It is a very variable species.

Habitat.— West coast of United States.

The Zigzag Periwinkle (L. ziczac, Dillw.), has a tall spire, angled at its periphery, and decorated with fine, zigzag stripes of brownish yellow from apex to base. The body whorl shows a median clouding of blue that is faintly seen on the upper whorls. The species is variable. Length, I to i inch.

Florida Keys, West Indies.

L. angulifera,

Lam., is distributed on the Florida and Gulf coasts and in the West Indies.

Genus TECTARIUS, Val.

The Pagoda Littorina

(T. Pagod, Linn.) is very much like a Chinese pagoda, with a row of upturned, triangular tubercles finishincr the keeled margins of its whorls. Secondary tubercles 176 The Periwinkles and Chink Shells in oblique rows cross the spaces intermediate between the keels, and granulations cover the whole surface. The body whorl has a double set of strong tubercles and a smaller row between these. The simple aperture is ribbed inside and tinted with the pale chestnut that stains and streaks the colourless exterior. Alti tude, 2 inches.

Habitat.—Australia, Ceylon.

The Prickly Littorina (T. muricata, Linn.) has a solid, yellowish gray shell with rounded whorls a little flattened below the sutures and beaded with sharp nodules along the spiral ribs. The aperture is nearly smooth, and brownish. This creature has lived a year in a cabinet, cheerfully taking up its aquatic life again when released. Length, i inch.

Habitat.— Bahamas, West Indies, Florida.

T. nodulosus,

Gmel., is smaller, to 3 inch long, dull olive green or brownish yellow, spirally double-keeled and beaded, with aperture smooth and brown. This "worthless Littorina," as Reeve calls it, has a world-wide distribution.

Habitat.— North Carolina to West Indies, Ceylon, Philippines, Australia.